When you only need view structure, don't call handle_derived with
DT_CREATE and rely on its internal hackish check to skip DT_CREATE.
Because handle_derived is called from many different places,
and this internal hackish check is indiscriminative.

Instead, just don't ask handle_derived to do DT_CREATE
if you don't want it to do DT_CREATE.

Fix a race condition in the testcase. The testcase assumed that
State='Sending data' means that the thread is already in an
InnoDB lock wait. This is not case, there is a gap between the
state changing to Sending data and execution reaching the point
where it is waiting for a lock.

Use a more precise check instead, through I_S.INNODB_TRX.

Problem:
========
180511 11:07:58 [ERROR] Slave I/O: Unexpected master's heartbeat data:
heartbeat is not compatible with local info;the event's data: log_file_name
mysql-bin.000009 log_pos 1054262041, Error_code: 1623

Analysis:
=========
In replication setup when master server doesn't have any events to send to
slave server it sends an 'Heartbeat_log_event'. This event carries the
current binary log filename and offset details. The offset values is stored
within 4 bytes of event header. When the size of binary log is higher than
UINT32_MAX the log_pos values will not fit in 4 bytes memory.  It overflows
and hence slave stops with an error.

Fix:
===
Since we cannot extend the common_header of Log_event class, a greater than
4GB value of Log_event::log_pos is made to be transported with a HeartBeat
event's sub-header.  Log_event::log_pos in such case is set to zero to
indicate that the 8 byte sub-header is allocated in the event.

In case of cross version replication following behaviour is expected

OLD - Server without fix
NEW - Server with fix

OLD<->NEW : works bidirectionally as long as the binlog offset is
            (normally) within 4GB.

When log_pos > UINT32_MAX
OLD->NEW  : The 'log_pos' is bound to overflow and NEW slave may report
            an invalid event/incompatible heart beat event error.
NEW->OLD  : Since patched server sets log_pos=0 on overflow, OLD slave will
            report invalid event error.

- Fixing post-push failure of innodb_fts_misc_1 test case.

InnoDB tries to fetch the deleted doc ids for discarded
tablespace. In i_s_fts_deleted_generic_fill(), InnoDB needs
to check whether the table is discarded or not before fetching
deleted doc ids.

fil_ibd_load(): Remove a message that is basically saying that
everything works as expected. The other "Ignoring data file" message
about the presence of an extraneous file will be retained
(and expected by the test innodb.log_file_name).

This reverts commit 8880dff2.

This commits replaces the call of the function setup_tables() with
a call of the function setup_tables_and_check_access() in the method
Multiupdate_prelocking_strategy::handle_end().
There is no known bug that would require this change. However the change
aligns this piece of code with the code existed before the patch for
MDEV-24823.

Attempt to build MariaDB server on MacOS could result in
compilation errors like the following one:

  In file included from server-10.2/storage/perfschema/cursor_by_account.cc:28:
  In file included from server-10.2/include/my_global.h:287:
  In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/math.h:309:
  In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/type_traits:418:
    server-10.2/version:1:1: error: expected unqualified-id

    MYSQL_VERSION_MAJOR=10
    ^
  server-10.2/build.dir/include/my_config.h:529:29: note: expanded from macro 'MYSQL_VERSION_MAJOR'

This kind of compiler errors occur by the reson that compiler's system headers
contain the directive '#include <version>' and a compiler is invoked
with -I${CMAKE_SOURCE_DIR}.

The MariaDB source code root directory contains the file VERSION that is handled
by the compiler during processing the directive #include <version>
since file names on MacOS are case insensetive, so version and VERSION is treated as
the same file name.

To fix the issue the source code root directory should be removed from a list
of directories used by the compiler for include search path.

The problem is that sharing default expression among set instruction
leads to attempt access result field of function created in
other instruction runtime MEM_ROOT and already freed
(a bit different then MySQL problem).

Fix is the same as in MySQL (but no optimisation for constant), turn
DECLARE a, b, c type DEFAULT expr;
to
DECLARE a type DEFAULT expr, b type DEFAULT a, c type DEFAULT a;

Removed explicit InnoDB monitor startup and used just functions
to print current lock information.

Problem was that we should skip strict password validation on
applier nodes similarly as is done for slave nodes.

Replace unnecessary sleeps with real wait_conditions to make
sure correct cluster sizes.

Relax the assert condition. A locked table that did existed prior to
CREATE IF NOT EXIST, retains the MDL_NO_SHARED_READ_WRITE MDL lock prio.

plugin variables in SET  only locked the plugin till the end of the
statement. If SET with a plugin variable was prepared, it was possible
to uninstall the plugin before EXECUTE. Then EXECUTE would crash,
trying to resolve a now-invalid pointer to a disappeared variable.

Fix: keep plugins locked until the prepared statement is closed.

encourage the use of mysql_secure_installation,
that can always set the root password correctly for all root accounts,
no matter how many are there and what the structure of privilege tables is

InnoDB startup hangs if a DDL transaction needs to be
rolled back and a recovered transaction on statistics
tables exists. In that case, InnoDB should rollback
the transaction which holds locks on innodb_table_stats
or innodb_index_stats during trx_rollback_or_clean_recovered().

InnoDB fails to fetch the index type when innodb dictionary
doesn't match with frm. InnoDB should return corrupted if it
can't find the index in ha_innobase::index_type().

table->move_fields wasn't undone in case of error.

1. move_fields is unconditionally undone even when error is occurred
2. cherry-pick an assertion in `ptr_in_record`, which is already in 10.5

The assertion is improved: storage engines like myisam always have to store
at least one field, so the assertion does not cover tables with no stored
columns.

So we are having a race condition of three of threads, resulting in a
deadlock backoff in purge, which is unexpected.

More precisely, the following happens:
T1: NOCOPY ALTER TABLE begins, and eventually it holds MDL_SHARED_NO_WRITE
 lock;
T2: FLUSH TABLES begins. it sets share->tdc->flushed = true
T3: purge on a record with virtual column begins. it is going to open a
 table. MDL_SHARED_READ lock is acquired therefore.
Since share->tdc->flushed is set, it waits for a TDC purge end.
T1: is going to elevate MDL LOCK to exclusive and therefore has to set
 other waiters to back off.
T3: receives VICTIM status, reports a DEADLOCK, sets OT_BACKOFF_AND_RETRY
 to Open_table_context::m_action

My fix is to allow opening table in purge while flushing. It is already
done the same way in other maintainance facilities like REPAIR TABLE.

Another way would be making an actual backoff, but Open_table_context
does not allow to distinguish it from other failure types, which still
seem to be unexpected. Making this would require hacking into
Open_table_context interface for no benefit, in comparison to passing
MYSQL_OPEN_IGNORE_FLUSH during table open.

innodb_debug_sync was introduced in commit
b393e2cb and reverted in
commit fc58c172 due to memory leak reported
by valgrind, see MDEV-21336.

The leak is now fixed by adding `rw_lock_free(&slot->debug_sync_lock)`
after background thread working loop is finished, and the patch is
reapplied, with respect to c++98 fixes by Marko.

The missing DEBUG_SYNC for MDEV-18546 in row0vers.cc is also reapplied.

Quoting MDEV reporter Daniel Lewart:

Starting MariaDB with default configuration causes the following problems:

    "[Warning] Could not increase number of max_open_files to more than 16384 (request: 32186)"
    silently reduces table_open_cache_instances from 8 (default) to 4

Default Server System Variables:

    extra_max_connections = 1
    max_connections = 151
    table_open_cache = 2000
    table_open_cache_instances = 8
    thread_pool_size = 4

LimitNOFILE=16834 is in the following files:

    support-files/mariadb.service.in
    support-files/mariadb@.service.in

Looking at sql/mysqld.cc lines 3837-3917:
wanted_files= (extra_files + max_connections + extra_max_connections +
tc_size * 2 * tc_instances);
wanted_files+= threadpool_size;

Plugging in the default values:
wanted_files = (30 + 151 + 1 + 2000 * 2 * 8 + 4) = 32186

However, systemd configuration has LimitNOFILE = 16384, which is far smaller.

I suggest increasing LimitNOFILE to 32768.

(trivial backport to 10.2)
Add a testcase

(trivial backport to 10.2)
The optimizer removes redundant GROUP BY operations. If GROUP BY element
is a subselect, it is "eliminated".

However one must not eliminate the item if it is used both in the select
list and in the GROUP BY, like so:

  select (select ... ) as SUBQ from ... group by SUBQ

Do not eliminate such items.

It is possible that an object that was originally created by
open_purge_table() will remain cached and reused for SQL execution.
Our previous fix wrongly assumed that ha_innobase::open() would
always be called before SQL execution starts. Therefore, we must
invoke dict_stats_init() in ha_innobase::info_low() instead of
only doing it in ha_innobase::open().

Note: Concurrent execution of dict_stats_init() on the same table
is possible, but it also was possible between two calls to
ha_innobase::open(), with no ill effects observed.

This should fix the assertion failure on stat_initialized.
A possibly easy way to reproduce it would have been
to run the server with innodb_force_recovery=2 (disable the purge of
history), update a table so that an indexed virtual column will be
affected, and finally restart the server normally (purge enabled),
to observe a crash when the table is accessed from SQL.

The problem was first observed and this fix verified by
Elena Stepanova. Also Thirunarayanan Balathandayuthapani
repeated the problem.

row_sel_sec_rec_is_for_clust_rec(): If the field in the
clustered index record stored off page, always fetch it,
also when the secondary index field has been built on the
entire column. This was broken ever since the InnoDB Plugin
for MySQL Server 5.1 introduced ROW_FORMAT=DYNAMIC and
ROW_FORMAT=COMPRESSED for InnoDB tables. That code was first
introduced in this tree in
commit 3945d5e5.

For the original ROW_FORMAT=REDUNDANT and the MySQL 5.0.3
ROW_FORMAT=COMPRESSED, there was no problem, because for
those tables we always stored at least a 768-byte prefix of
each column in the clustered index record.

row_sel_sec_rec_is_for_blob(): Allow prefix_len==0 for matching
the full column.

Before FRM is written walk vcol expressions through
check_table_name_processor() and check if field items match (db,
table_name) qualifier.

We cannot do this in check_vcol_func_processor() as there is already
no table name qualifiers in expressions of written and loaded FRM.

Buffer overflow in ib_push_warning() fixed by using vsnprintf().

InnoDB parser was obsoleted by MDEV-16417.

Thanks to Nikita Malyavin for review and suggestion.

It's Oracle libmysqlclient license exception, we no longer include,
build or ship libmysqlclient

Before this patch mergeable derived tables / view used in a multi-table
update / delete were merged before the preparation stage.
When the merge of a derived table / view is performed the on expression
attached to it is fixed and ANDed with the where condition of the select S
containing this derived table / view. It happens after the specification of
the derived table / view has been merged into S. If the ON expression refers
to a non existing field an error is reported and some other mergeable derived
tables / views remain unmerged. It's not a problem if the multi-table
update / delete statement is standalone. Yet if it is used in a stored
procedure the select with incompletely merged derived tables / views may
cause a problem for the second call of the procedure. This does not happen
for select queries using derived tables / views, because in this case their
specifications are merged after the preparation stage at which all ON
expressions are fixed.
This patch makes sure that merging of the derived tables / views used in a
multi-table update / delete statement is performed after the preparation
stage.

Approved by Oleksandr Byelkin <sanja@mariadb.com>